Abstract
Maize and teosintes are excellent systems for study of population and
ecological genomics, as well as teosintes provide excellent germplasm
resources for forage maize breeding. However, genetic relationship,
evolution, hybridization and introgression among the genus Zea species
have not been completely resolved and effective methods for Zea species
classification and identification are scarce. In current study, nuclear
(ITS), mitochondrial DNA (atp6, cob and nad1) and chloroplast DNA
sequences (matK, psbA-trnH and rbcL) were used to explore as a simple
and efficient DNA barcode for identification and genetic study of the
Zea species. Phylogenetic incongruence between nuclear and cytoplasmic
sequences detected in present study. The lowest divergence value from
pairwise comparisons were found between Z. mexicana and Z. parviglumis
based on combined six cytoplasmic sequences and Z. mexicana and maize
showed lowest divergence value based on ITS sequences. It is suggested
that single-gene data sets and combined data sets of six cytoplasmic
sequences failed to identify and classify every species at inter-species
level, however, the combined data set containing ITS and atp6 can
identify and classify Zea species perfectly. Moreover, the tetraploid Z.
perennis was confirmed an autotetraploid of diploid Z. diploperennis
reflecting from phylogenetic tree based on combined six cytoplasmic
sequences.